Add monitor and downtime APIs with integration tests.
Add API function for submitting service checks.
Clean up of the monitor API, better error message.
Add current_only param to list_downtime.
Pass the options in the monitor update in tests so they aren't clobbered.
Don't include name by default in create monitor API.
Tweak some API function names to match existing pattern.
Add optional parameter to filter returned group states, default to not returning per-group states.
Use a default value of `now` for service check timestamp.
Fix host parameter name for the service check API
Merge pull request #115 from DataDog/conor/monitor-apis

Add monitor and downtime APIs with integration tests.